The present invention relates generally to power amplifiers, and more particularly, to a broadband linearizer for use with a variety of power amplifiers having different gain and phase performance requirements.
Lockheed Martin Corporation has developed a broadband linearizer design that is implemented using passive FET technology. This broadband linearizer design is discussed in a paper entitled "Linearized Traveling Wave Tube Amplifiers for Space", by Shabbir Moochalla, published in 1998 IEEE MTT-S International Microwave Symposium & Exhibition "Advances in Amplifier Linearization Workshop", and "MMIC Linearizers for C and Ku-Band Satellite Applications" by R. Dorval. The Lockheed Martin approach is a totally different design approach compared to the present invention.
Nippon Electric Company (NEC) manufactures linearizers for use with power amplifiers. Such linearizers are disclosed in "INTELSAT-VII Linearizer for Ku-Band TWTA" report, and "Linearizer for Ku-Band TWTA Performance Specification" (Specification No. E021307). The NEC linearizers use commandable switched frequency bands to cover wide bandwidth. However, the basic design for each band of the NEC linearizer is narrow band.
Conventional linearizers do not provide for independent, flexible gain and phase control using a single design that can mate with different kinds of power amplifiers having various gain and phase performance. Conventional linearizers also do not provide for a simple, compact, low cost design that does not involve complex commandable switched band selection operation.
Accordingly, it would be advantageous to have a broadband linearizer that may be used with a power amplifier that improves the linearity and efficiency performance of the power amplifier across a wide frequency bandwidth. It would also be advantageous to have a broadband linearizer that may be used with a variety of power amplifiers having different gain and phase performance requirements.